The invention concerns a method for manufacturing elastic pants.
It is known from the prior art to manufacture elastic pants, and especially elastic underwear, from surface elastic materials. By using such surface elastic materials, the underwear, which is usually located close to the skin, is made noticeably more comfortable to wear, as the underwear sits well, while at the same time exerts comparatively low surface pressure on the body, as the force-fit connection to the skin over the entire contact surface of the underwear necessary for the underwear to hold in the way required and sit properly is achieved.
A method for manufacturing such a surface elastic textile material, that can especially be used to manufacture underwear, is described in the publication EP 1 753 618 B1. With this method, a plan web material is continuously transported in a longitudinal direction of the web material and folded over an elongated rod-like or tubular shaping core into a convex tubular closed form. The tube formed in this way forms a first outer layer, to the outer surface of which elastic threads are applied in the form of a tubular reinforcement, wherein the elastic threads are prestressed when they are applied to the first outer layer, so that, if the first outer layer or the tube is removed from the shaping core, the first outer layer is tapered by forces impacting on the tube from the elastic threads in a radial direction of the tube.
A second outer layer is subsequently likewise applied to the elastic threads from a plan web material, and connected with the elastic threads. The tubular web material formed in this way is thereupon cut open in a longitudinal direction, wherein only the elastic threads need to be severed, as the first outer layer folded in a tubular form and the second outer layer are placed, in relation to one another, in such a way that the tubular web material can be cut open along a line, whereby the end sections of the first outer layer, as well as the second outer layer are always adjacent to one another. In this way, the tubular web material can be unfolded along said line to form a surface elastic web material once the elastic threads have been severed, and may, for example, subsequently be processed to produce underwear.
With the methods known from the prior art, in order to manufacture the underwear, the surface elastic web material is initially manufactured and this is then subsequently processed further in additional stages of processing, in a known way, to create underwear.
It is desirable to continue to develop the elastic pants made out of a surface elastic material, known from the prior art, in such a way that the elastic pants can be easily and cost-effectively manufactured in a single manufacturing process.
In accordance with an aspect of the invention a method is provided for continuously manufacturing elastic pants wherein a plan web material is continuously transported in a longitudinal direction of the web material, is formed into a tube and is closed in the longitudinal direction, wherein the closed tube forms a first outer layer and wherein the first outer layer subsequently wound around with elastic threads in the transport direction in the form of a tubular reinforcement, so that the elastic threads are taut when the outer layer has a convex shape, wherein a second outer layer subsequently and continuously applied to the elastic threads in the transport direction and connected to the elastic threads and/or the first outer layer, wherein the first outer layer, the elastic threads and the second outer layer form an elastic web material for pants, characterized in that subsequently the wet material for pants is closed at regular intervals along a joining section, so that two opening sections of approximately the same size are formed by the joining section in transverse direction as to oppose one another, and wherein subsequently the web material for pants is cut at a distance to the joining sections in the transport direction, thereby forming elastic pants.
Use is made of the method for manufacturing surface elastic materials known from the prior art and described at the beginning, when manufacturing the elastic pants, wherein, unlike with that method, the first outer layer is, for example, sealed by welding, an adhesive bond or similar, whereas, with the method known from the prior art, the elastic web material is merely folded to form the tube, wherein the end sections of the elastic web material lie adjacent to one another and are not connected to one another. In order to seal the tube, the tube can either be formed in such a way that the end sections of the unfolded web material overlap with one another and the overlapping end sections are connected with one another in the area of overlap, or can also be manufactured by the web material being folded in such a way that lateral edges of the folded web material lie adjacent to one another and the end sections adjoining the lateral edges are, for example, connected to one another by a seam or similar. According to the invention, it is provided for that the second outer layer can also be sealed in a comparable way.
The web material is preferably a non-woven material, a web material, a film or a multi-layer laminate from this or comparable materials. The elastic threads used to manufacture the tubular reinforcement can, according to the invention, be manufactured, among other things, from spandex, rubber, synthetic rubber or comparable materials.
When the elastic threads are arranged on the first outer layer, it is possible to either resort to the method known from the prior art, involving the first outer layer being brought into a convex shape and the elastic threads being applied to the first outer layer under prestress. It is, however, also possible to taper the first outer layer, and apply the elastic threads to the tapered outer layer, either without any prestressing or with only a small amount of prestressing.
According to the invention, the second outer layer is manufactured from a plan web material, wherein comparable materials can be used, which are also used to manufacture the first outer layer.
The pants are manufactured from the web material for pants, by the web material for pants being sealed along the length of the joining section at regular intervals. The sealing along the joining section may be performed using welding, adhesion or similar. In the process, interior surfaces of the first outer layer are connected with one another in the joining section.
It is expedient for the connection in the joining section to be designed in a linear fashion, and preferably show an arched contour. When the pants manufactured with the help of the method in accordance with the invention are worn, the connection occurs in the stride of the person wearing the pants, so that, as per the invention, the arched contour is adapted to the body contour in this area.
Through the connection in the joining section, the web material for pants is sealed in the transverse direction, i.e. transverse to the direction of transport of the web material for pants, in such a way that the tubular web material for pants in the section in which the joining section is located, is divided by the connection into two tubular areas.
In order to manufacture the pants, the web material for pants sealed in the joining section is severed at a distance to the joining section, as a result of which the elastic pants are formed. The severing can be performed using a contoured profile adapted to the shape of the body, in order to be able to manufacture various different models of pants, such as underpants or boxer shorts. Through the web material for pants being severed at regular intervals, pants are constantly being manufactured in the course of the manufacturing process.
In order to simplify the manufacture and save on material, it is provided for by the invention that the web material is severed between two inversely designed joining sections, that are manufactured at a distance to one another, so that two inversely designed pairs of pants are manufactured in each case.
In order to connect the first outer layer, the elastic threads and the second outer layer with one another, it is provided for, in accordance with the invention, that an adhesive is applied to the elastic threads. It is, however, also possible and provided for in accordance with the invention to connect the second outer layer with the first outer layer, for example by welding or similar, wherein the connecting points used for this are designed in such a way that the elastic effect of the elastic threads is not impaired. According to the invention, the various different connections possible can also be combined, so that a welding connection can, for example, be used in addition to an adhesive connection.
It is advantageously provided for, in accordance with the invention, that the web material for pants is continuously spread and pulled in a flat shape before producing the joining section. The joining section can, in this way, be manufactured in an especially simple way, such as through welding. In the case of the web material for pants pulled into the flat shape, the joining section is placed in a central area between two longitudinal sides of the web material for pants running in the longitudinal direction of the web material for pants.
In the case of a further advantageous embodiment of the method in accordance with the invention, it is provided for that the first outer layer and the elastic threads are continuously spread and pulled in a flat shape before applying the second outer layer. The arrangement of the second outer layer on the elastic threads can, in this way, be simplified considerably.
In order to be able to simply place the second outer layer on the first outer layer pulled into the flat shape, it is, according to the invention, provided for that the second outer layer is produced from two sublayers, wherein the two sublayers are applied to opposite sides of the spread first outer layer and the elastic threads. The sublayers can be manufactured from an elastic web material by separating off the elastic web material or by unfolding the elastic web material along a central line running between the longitudinal sides of the elastic web material. It is, however, also possible, and provided for in accordance with the invention, that different webs of a web material can be used for manufacturing the sublayers wherein different web materials can also be used to advantage, for example to make different properties of the front of a pair of pants and the back of a pair of pants possible.
In order to further influence the properties of the elastic pants, it is provided for, in accordance with the invention, that elastic threads are also applied to the second outer layer in the form of a tubular reinforcement and a third outer layer is applied to these elastic threads. The third outer layer and the elastic threads can, in turn, be manufactured from the same materials as the first and second outer layers, as well as the elastic threads already used and applied to the first outer layer. The first outer layer, the second outer layer, the third outer layer and the elastic threads located between the layers constitute the web material for pants. The third outer layer can, according to the invention, be processed in the same way as the first and second outer layers.
The method in accordance with the invention is also suitable for manufacturing disposable diapers or similar. In particular in this respect, it is provided for, in accordance with the invention, that a granular material and/or a fibrous material is arranged between the first outer layer and the second outer layer and/or between the second outer layer and the third outer layer. The granular material may, according to the invention, concern a superabsorber, which can take up a comparatively large quantity of liquid.
According to the invention, it is in particular provided for, in regard to the manufacture of disposable diapers, that the first outer layer and/or the second outer layer and/or the third outer layer is manufactured from a hydrophobic or a hydrophilic material. The properties of the disposable diapers can be influenced in this way, because it can be achieved, by making a suitable choice of the material used to manufacture the layers, that moisture from the person wearing the disposable diapers is quickly transported from his or her body in the direction of the second outer layer or the third outer layer, wherein it can simultaneously be avoided that moisture leaks out of the second outer layer or the third outer layer or back to the first outer layer, and is transported through the first outer layer.
In order to achieve a sufficient surface elasticity of the pants manufactured, it is provided for, in accordance with the invention, that a length of the elastic threads corresponds to 120% to 500% of the length of the elastic threads in the untensioned state, if the first outer layer has a convex shape. The convex shape, within the meaning of this invention, is characterized in that the first outer layer is fully spread out, so that all the connecting lines of two points of a perimeter running in a transverse direction of the first outer layer nm entirely within said perimeter.
In order to be able to influence the surface elasticity of the pants manufactured on an area-by-area basis, it is provided for, in accordance with the invention, that at least one elastic thread consists of or comprises a material different from that of the remaining elastic threads. For example, threads of differing elasticity can be used, wherein some threads can be provided for to improve the stability and durability of the pants manufactured, and other threads can serve the purpose of providing the necessary surface elasticity.
In order to manufacture the tubular first outer layer, it is provided for, in accordance with the invention, that the plan web material is continuously folded in the longitudinal direction of the web material to form the closed tube over an elongated shaping core, wherein the shaping core is designed in such a way that the tube has a convex shape.
It is, according, to the invention, advantageously provided for that a shape of the second outer layer and/or the third outer layer is adapted to the convex shape of the first outer layer and is thus applied to the elastic threads. According to the invention, the second outer layer and/or the third outer layer can, in a comparable way, be folded into a tubular form via the first outer layer folded over the shaping core and the elastic threads placed on the first outer layer.
It is advantageously provided for in accordance with the invention that the elastic threads are applied to the first outer layer and/or the second outer layer under prestress.
In order to be able to apply the elastic threads to the first outer layer, it is provided for, in accordance with the invention, that the elastic threads are wound on thread bobbins, wherein the thread bobbins are arranged on at least one planetary gear, wherein the first outer layer is guided through the planetary gear in the convex shape, wherein the planetary gear is caused to rotate around the first outer layer and wherein the elastic threads are continuously un-wound from the thread bobbins and applied to the first outer layer. By analogy, elastic threads can also be applied to the second outer layer.
A central axis of the planetary gear may, in accordance with the invention, run axially to a central axis of the tubular unfolded first outer layer running in the direction of transport. In order to influence the course or the direction of the elastic threads on the first outer layer, it is, however, also possible, and provided for in accordance with the invention, for the central axis of the planetary gear and the central axis of the first outer layer to be at an angle to one another. According to the invention, it is, in this way, possible for the elastic threads to run, on an area-by-area basis, in the transverse direction on the first outer layer. The planetary gear used to arrange the elastic threads on the second outer layer can be aligned analogously as well.
In order to influence the properties of the elastic pants, and especially in order to influence the surface elasticity of the pants, it is provided for, in accordance with the invention, that unwinding velocities are differentiated from one another when unwinding the elastic threads from different thread bobbins.